There is some factual and some not so factual information in this thread about modified and undermodified malts. I can not address them all in one response. Let me address the original question.
Steve973, unless you are malting the grain yourself or work for a malting company, I am not sure you can secure a commercially produced undermodified malt. What particular malt were you considering for undermodified malt? If it domestic malt, its well modified. Even if it European malt, it is well modified. Unless the maltster has taken steps to undermodify it, today's malting barley varieties produce well modified malts.
I see you are making an adjunct beer. Unless you have had problems with run off of this beer in the past, I don't see any reason to do a glucan rest. Beta glucans are generally broken down fairly well in the malting process and again, with todays barley varieties, glucans are not generally a problem. Brewers only see glucan problems in their run off when they use a good portion of unmalted grains Flaked barley, oat, etc) in their recipes. You are adding starch or sugar as adjunct and not unmalted grain so I suggest you skip the glucanase rest unless you just want to do it for the experience.
To determine whether you need a protein rest for your adjunct beer I need a little more information. You say you will be using 4 lbs in a 10 gallon batch. 4lbs of what (sucrose, glucose, starch, ?)? How much base malt (Pilsen, or whatever) is used? Is it 2 row or 6 row base malt? What is you starting target gravity? The way to think of this is that if you are adding 4 lbs of starch with 4 lbs of base malt to make a light beer, you are probalby diluting the FAN sufficiently that you want to do a protein rest. However, if you are adding 4 lbs of starct to 10 lbs of base malt you can skip the protein rest as the FAN will be fine for fermentation.
As far as the 2 saccarifications rest, the information here seems to be in line with the optimum conditions for alpha and beta amylase. I do not have an opinion on step versus infusion mashing to get sugar profiles. I tend to do my mashes at the lower saccharification temperatures if I want a drier crisp beer like in certian lagers and infusion mashes for ales with more body.
One last thing, modification of commerical malts is not related to maltiness. Maltiness comes from the degree of heat applied to the malt in kilning. Thus, higher colored kilned dried malts like Munich malts are more malty in flavor than base malts and Munich 20 is maltier than Munich 10. If you want maltiness, add more Munich malt.
Thanks.
I hope this helps as I have much experience in malts and malting.
Dr Malt