RIMS build complete now I have questions

So a little backround I'm still relatively new to brewing (1 1/2 years or so) and I got the bug bad. Started with 5 gallon batches and they never lasted long enough. Gathered more stuff and started partial mash and AG brewing. Then it was time to go bigger so now I have a single tier RIMS setup with 3 keggles and 2 banjo burners. So i just fired it up and brewed 2 batches over the last week. I've gotten 70 % efficiency on both batches but they haven't been without some misshaps. The MLT is a Keggle wrapped in 2 sheet of reflectix a 15" false bottom and a bottom drain. Do you guys add extra water to the mashtun to account for the deadspace under the false bottom? I don't usually have to recirculate till 20 mins or so after I mash in, but after that some of the water is going to be in the tubing and RIMS tube. So during the mash it seems like there is a gallon at least of wort/water not in contact with my grain. I think this made me have some trouble with gettin my wort really clear because I always seemed to be disturbing the top of the grain bed due to my lack of water on top of it. I think thats it for now thanks for your help. I'll post some pics of the rig once I get out of work

It sounds like you are not adding in enough strike water to account for the deadspace in your mash tun and RIMS plumbing.