Advice on holster for daily wear - driving, running, in and out of trucks, wearing a backpack, and sweating. Beretta 81 or Zavasta M88

Looking for recomendations on an IWB or OWB that fits rear right, holds a Beretta 81 or an M88 and is comfortable for long active and sweaty days. I do field work in the south with lots of hiking, scrambling through brush, moto riding, pack wearing, and getting in and out of trucks and UTVs. I'd prefer my gun was concelead, had an extra mag, and was able to be removed or put on quickly without undoing my belt. Good retention when sitting, climbing, crawling is key.A "chassis" style holster that has holders for both the beretta and m88 would be awesome.Any thoughts or am I looking for unicorn?Shaping a kydex holster that bolts to a good base system seems within my abilities if that is best option for my older pistols.Thanks in advance for your knowledge. via /r/CCW https://ift.tt/38Q2NGA