-L is a low ride, while -H is a high ride.
The Tactical Solutions Trail-Lite Holster for Browning Buck Mark Pistols are designed for right hand shooters only. I would recommend the TANDEMKROSS Side Switch Nylon Holster, found by using the link below:
https://www.opticsplanet.com/tandemkross-side-switch-nylon-holster-for-ruger-mk-series-22-45-browning-buck-ma.html
The Tactical Solutions Trail-Lite Holster is designed to fit the Browning Buck Mark .22LR pistols with or without an optic. Tactical Solutions does not specify if this holster will fit the Ruger Mark IV. I would recommend reaching out to them or going with a dedicated Ruger Mark IV holster.
https://www.opticsplanet.com/desantis-right-hand-tan-the-woodsman-reg-097tclaz0.html?_iv_gun-model=ruger-mark-iv-22-sl-45
Yes, it will fit that pistol.
Direct response from manufacturer: "The holster we have made for us for the Browning Buckmark should accommodate the full length rail on top."
Unfortunately this will not fit the S&W SW22 Victory.