An RF-sensing amp will always exhibit a transient high VSWR event during TX switchover, as it switches AFTER RF is already applied, as will a switched-element tuner as it does its switching gyrations.
When I am using a tuner I will place my QRP-O-Meter between the transceiver and the tuner.? I put the QRP-O-Meter into the VSWR position which inserts a 6-dB loss VSWR bridge; the loss of the bridge will keep the VSWR under 2:1 under all load VSWRs.? After tuning is done I bypass the bridge.? Of course your tuner must be able to tune with the attenuated TX power level.
When I use an amp I connect a TX line and use that to key the amp; hot-switching avoided.
73, Don N2VGU.
Donald S Brant Jr